Lazy motor after fall (and replacement)

A few weeks ago, my Phantom fell from 30-40 feet straight down. I had failed to tighten a prop which dropped in flight. I was able to pick up all pieces.

One arm in the shell was badly bent, deformed, unrepairable, one ESC slightly bent. The compass cable was torn, the gimbal damaged. I replaced the shell and the compass cable.

After those repairs I did a check flight and noticed a motor was lazy during the startup sequence. While it might be the one that got damaged, I wasn't sure. I replaced the motor (new motors with black caps which is tightened counter-clock wise - it is a clock-wise motor) but the symptoms were the same (startup sequence, not necessarily visible in flight)

At first spin, that motor and prop turn slowly as if working hard (though they're not hitting anything) if I go full throttle, the Phantom takes off and seems to fly ok. Of course I am paranoid and I feel it's not flying as well as it used to, Att mode tends to drift more I think and GPS mode doesn't loiter as well as I remember it did. Also, I can't fly more than 4 minutes with a Gimbal, 9.5 minutes without any payload

1) Where do you think that lazy motor (before full throttle) issue comes from?
2) I think that DJI ESC don't need calibration but this looks just like its calibration is off, no?
3) Am I paranoid about the higher battery drain you think?
4) Is it ok to run one black prop motor, provided it's the right rotation?

Sounds like you've got a bad ESC. Depending on whether it's on the front or rear, you need to choose between green and red, which control the color of the Phantom's LED lights. You can buy an ESC for about $18.00.

Sounds like you've got a bad ESC. Depending on whether it's on the front or rear, you need to choose between green and red, which control the color of the Phantom's LED lights. You can buy an ESC for about $18.00.

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I have a similar problem. The prop on one arm wants to move slower than the rest. I have already replaced the prop, the motor, and the ESC. In my case, it won't fly because that prop won't provide its share of lift. My Phantom just tries to flip over. What next???

(Are front ESCs different from rear? Is there a chance my problem is from installing a Front onto a Rear Arm?)